Press



Sept. 3, 1946. H. v; ALLISON V-IPRESS mm m. 1. 194:

2 Sheets-Shoot 1' awe/WW0 V. ALLISON p 6- H. v. ALusoN 2,407,123

PRESS Filed 0a. 1. 1943 2 Sheets-Shoot 2 Elma/mm Emma;

Patented Sept. 3, 1946 UNITED STATES PATENT OFFICE PRESS Hugh V. Allison, Fail-field, Conn., assignor to The Allison Company, Bridgeport, Comp, a corporation of, Connecticut V Application October 1, 1943, Serial No. 504,636

- 1 Claim.

This invention relates. to new and useful im provements in presses and has particular rela tion to molding presses. i

The objects and advantages of. the invention will become apparent from a consideration of the following detailed descriptiontaken in connection with the accompanying drawings wherein a satisfactory embodiment of the invention is shown. However, it is to be understood that the invention is not limited to the details disclosed but includes all such variations and modifications as fall within the spirit of the invention and the scope of the appended claims.

In the drawings:

Fig. 1,is a view partly in front elevation and partly in section and showing a press made in accordance with the teaching of the invention;

Fig. 2 is a view similar to Fig. 1 but showing the press in open position and with a piece of work ejected and supported by the lower or pressure ram;

Fig. 3 is a vertical sectional view on a somewhat larger scale through the central portion of the press when closed;

Fig. 4 is a sectional view showing a step in the separation of the molded piece from a bottom die plate;

Fig. 5 is a similar view showing the parts sepa rated; and

Fig. 6 is a plan view of the bottom die plate.

While the invention is herein illustrated applied to the manufacture of abrasive articles, as grinding wheels, it is to be understood that the invention has many other applications. For example, the press of the invention may be used in powdered metallurgy, in plastic molding, etc., and the claims of this application are intended. to include these as well as other uses to which invention may be applied.

Referring in detail to the drawings the press of the invention as herein shown comprises a frame generally designated l and including a bed H and a head l2 together with connecting uprights l3 and I4 supporting the head from the bed and having other functions as wiil appear. Supported between the bed I I and the head 52 by the uprights l3 and I4 (which are shown as trans versely round posts) is a die holder comprising a web or plate 15 having a thickened central portion It provided with an opening Hextending vertically therethrough. Plate is shown as having split end portions l8 and I9 about the respective posts or uprights and these split portions are adapted to be drawn together about the uprights on tightening of screws wwvhereby to s secure the die holder in the desired position of vertical adjustment relative to the bed and the head.

Supported by the die holder 15 is a mold ring generally designated 2| and comprising a skirt portion 22 of an outer diameter to enter the hole or opening I! a radially enlarged portion 23 at one end providing a strengthened portion and a shoulder 24 disposed. against the upper side of the thickened central portion it of the holder l5. Ring 2! Units skirt portion 22 is of an outside diameter to have a tight or pressed fit in the open* ing H. The ringis removable from the holder for replacement by a ring having a larger or smaller internal diameter than that shown whereby articles of the desired diameter may be molded.

Apressure ram 25 is shown as movable through the bed H and this ram, at least its inner or upper portion, is of a diameter a few thousandths less than the internal diameter of ring 2! to enter the mold ring and be freely movable therein with-- out contacting the sides thereof. The precise manner in which the ram 25, orother pressure applying means if some other means is employed. is moved is not a limiting feature of the invention. As shown the lower end of the ram is movable in a cylinder 2.5 to the lower end of which fluid under pressure may be supplied as through a passage H. The fluid may be exhausted through the same passage or otherwise to permit of retraction or downward movement of the ram in the cylinder 2'6 and relative to the mold ring 2 though it is noted that the ram"i.s never entirely withdrawn from the mold ring.

Within the mold ring 2| and on the upper end of the ram 26is a bottom die plate 28 also having a free or loose fit in the ring. This plate is provided with a central upwardly extending por-- tion 28 comprising a molding core and which may be integral with the plate as shown or otherwise fixed thereto. A predetermined number of holes M are provided in the plate 2'8 in predetermined relation to the stud or core 29 and the purpose of these holes will appear. Further it will appear that these holes or openings 30 may be in the form of notches opening through the edges of the plateif that is desired.

Disposed on the upper side of bottom plate 28 is an inner die plate 3! of a diameter to have a snug fit in the ring 2! but yet to be movable into and out of such ring. Plate Iii has a central opening receiving the core 29 of plate 28 so that plate 3| is disposed flat against the upper side of plate 28 when the parts are in the mold ring 2!. Aside from its central opening for the reception or passage of the core 29 plate 3! is imperforate.

Operable through the head [2 is a holding ram 32 to the upper endof which is connected the lowerend or thinner end' of a piston rod 33. A

the upper and lower sides of the piston as lower end of the ram 32 as by machine screws.

40 or otherwise as may be desired. The closure plate has an opening or recess 4| to receive, freely, the upper end of the core or projection 29 when the press is closed as in Figs. 1 and 3. Since the closure plate 39 is removable from the lower end of the holding ram 32 it will be understood that this plate may be replaced by another of greater or lesser diameter or having a larger or smaller hole or recess 4|, etc.

When an article is to be molded the pressure ram 25 is located with its upper end within the mold ring 2| as in Figs. 1 and 3. The inner die plate 3| is disposed on the bottom die plate 28 and this assembly placed within the ring 2| and on the upper or inner end of the ram 25. Alternatively the bottom plate 28 may be dropped into the ring 2| onto the upper end of the ram 25 and thereafter the inner die plate 30 may be placed on plate 28. In either case the parts are arranged with the core 29 passing through the inner die plate.

Now (at this time the holding ram 32 and the closure plate 39 are in an upper or retracted position) the proper amount of material to be molded is placed within the ring 2| on the plate 3| which has a snug fit in the ring as above set forth. The holding ram is then lowered to move the closure plate 39 into the position shown in Figs. 1 and 3 and wherein said plate is closing the upper end of the mold ring 2|. Then pressure ram 25 is moved further into the mold ring 2| forcing the plates 28 and 3| upwardly therein and pressing the moldable material against the closure plate 39, the inner die plate 3| and the inner wall of the mold ring and about the core 29. Clearly the mold ring has an inner configuration corresponding with the desired outer configuration of the articles being molded.

The moldable material which is here disclosed as an abrasive compound comprising abrasive grain, fillers, a binder, curing agents, etc., is placed on the plate 3| in a measured quantity. After it is pressed or molded into the shape of a wheel 42 shown in the drawing (or other desired shape) the holding ram 32 is raised or retracted. Then the pressure ram 25 is moved further into and in fact through the mold ring 2| to eject the bottom plate 28, the inner plate 3| and the molded wheel 42 from the mold ring 2|.

Thus the parts are moved to the relative positions in which they are shown in Fig. 2. There it is noted that both the die plates and the newly molded wheel 42 are held above the mold ring by the lower or pressure ram 25. It will be understood that in the molding operation there is a tendency to mold the material to the inner surface of the mold ring 2| and that the lower ram acts as an ejector forcing the plates and the newly molded article from the mold ring.

With the parts positioned as in Fig.2 the operator lifts the plates and the newly molded article from the upper end of the ram 25. This may be done by grasping the upper end of the core 29 or by lifting from the edges and the under side of the plat 29. At this time the article or wheel 42 may be soft and readily deformable. If the finished product is to be a grinding wheel the article 42 will likely contain water and. be soft and deformable prior to final 4 curing. Thus it should not be touched as it comes from the press and is lifted on the plates 28 and 3|.

When the plates and the newly molded article are lifted from the upper end of the ram 25 they ar taken to a separating means preferably located conveniently adjacent the press. This means, generally designated 43, comprises a supporting base or plate 44 having upstanding pins 45 in the number and spaced relation of the holes or openings 39 in the bottom die plate 28. The operator places the plates 28 and 3| and the article 42 on the pins 45 with the latter aligned with and entering the openings 30 in the bottom die plate 28 as in Fig. 4. Then pressure is applied to the upper end of the core29 as by a plunger 46 or the like and the bottom die plate 28 is pushed downwardly over the pins 45 and toward the base 44 leaving the inner die plate 3| and the article 42 supported on the upper ends of the pins 45.

Now the plate 3| and the article 42 thereon are removed from the pins and the article while supported on the plate 3| may be transported to an oven or to a sheet on which it is to be placed in an oven or the like for final cure. In any event direct handling of the newly molded article is avoided. Thereafter the plate 28 is again placed in the mold ring on the upper end of the pressure ram 25 and if the work has been removed from the plate 3| it is again used and if it has been placed in an oven or the like a new plate 3! is used and the above described cycle of operation is repeated.

It will be understood that the main purpose of the core 29 is to form a central opening through the article being molded. This is important in the molding of abrasive wheels and the like but where a central opening is not required (or in fact where no opening is required in the product) the core 29 may be omitted. Where openings other than central openings are required in the product the core 29 or a plurality of such cores may be suitably located on the bottom die plate and the inner die plate will be provided with openings for their passage. The rams may be operated other than hydraulically and the top and bottom rams may move upwardly together when the finished work is being removed from the mold ring and in such instance the top ram may move faster than the pressure ram or while at the same speed may move a greater distance to expose the ejected work for removal from the lower or pressure ram.

Having thus set forth the nature of my invention, what I claim is:

In a machine for molding articles, a die holder having a vertical opening therethrough, means for closing the upper side of said opening, a ram movable into and through said die holder from the lower side thereof, a pair of dieplates insertable into and removable from said die holder, said pair of die plates comprising a bottom die plate resting on said ram when in said die holder, a centrally located core projecting from the upper side of said die plate, an inner die plate on said bottom die plate and having a centrally located opening through which said core projects, said bottom die plate having holes therethrough in spaced relation to said core, and said ram when moved through said die holder adapted to move said die plates out through the upper side of the latter.

HUGH V. ALLISON. 

